Field system for motor electric meters.



(. W, .BUSCH .FIELD SYSTHlNI FOM MOTOR. ELECTRIC M-ACVERS.

'APPLIGA'VKUN FILED MAR.16,'!)5

Patented Jan.25,1910.

LLM

dwf-m i the lother hand on account ot the appear- UNITED STATES PATEN T OFFICE.

CARL WILHELM JOHN BUSCH, OF PINNEBERG, GERMANY, ASSIGNOR OF ONE-HALF To HUGO RoosEN, oF

FIELD SYSTEM FOR MOT MUNICH, GERMANY.

OR ELECTRIC METERS.

Patented J an. 25, 1910.

Application filed March 18, 1905. Serial No. 250,868.

T o all lwho/m it may concern:

Be it known that I, CARL runnen Jona' BUSCH, a subject of the German Emperor, and resident of Iiimeberg, in the Province of Schleswig-Holstein and Kingdom ot Prussia, in the German Empire, have invented certain new and useful Improvements in Field Systems for Motor Electric Meters, such as VVattmetei-s and the Like, of which the following is a specification.

As is known, electric meters without iron possess the disadvantage that on account of the weak fields the force of the system is only a small one, whence result mechanical irregularities, whereas outer fields cause considerable disturbances or laults of the Iexactness .or accuracy ot' the statement:- of the meter. But by arrangingr iron in the path of the lines of force, on the one hand the proportionality will be disttn'bed,' on

ances of hysteresis the motion of the meter under a low load will be dependent' ou previous higher loads of the meter, so that particularly when the meter has been overloaded, for example by short-circuiting, there remains also without workingcurrent a remanent field, which causes the watthour-ineter to be inoperative'or run idle.

The object of the present invention is, to render possible the application ot' iron and to obviate at the same time the disadvantages above stated. V

The object aimed at is attained by allowing thev field produced by the working` current to pass but partially through the armature and by short-cireuiting tht` other part of the field without crossing the armature through an iron-path or iron connection which may be provided with one or more air gaps.

In the accompanying drawingsFigure l is a' diagrammatic 'representation ot the field magnet of an electric meter which may be used with a disk-:uhxature and being con-` structed in accordance with and embodying my invention; Fig. 2 is likewise a diagrammatic view, showing a nualitication; Fig. 3 is a similar view-showing a further modification, and Fig. 4 is a diagram illustrating` the action of the modified meters.

Similar letters of reference refer to similar parts throughout the several figures.

a is 4the coil through which the direct working current is passed, b the iron-frame, c the air space or field in which the armature-disk rotates, (,l-(Z indicates the axis of rotation oi the armature, e is the iron return-coinluctor for the lines of force crossing or traversing the armature, f the ironshunt. or auxiliary-conductor for the magnetic lines oi force-which do .not traverse or cross the armature, and g an air-gap which may be provided in the said shunt-conductor f it desired. The course and direction ol the magnetic lines of force are indicated by dashed and dotted lines and arrow-heads.

After the current has ceased in the coil a, a nnngneto-motive. force or remanence remains in the iron-frame Z) which force sends out lines of force through the magnetic core. The :unount of the said magnetof torce depends upon the length of the iron path in the trame l), the induction (that Iis to say, the strength of current which haspreviously passed the coil) and the magnetic properties of the material. Also in the magnetic shunt members f' there remains a magneto-motive force, which produces lines of force ot the same direction.

The magnet shunt conductors are malgnetized by the passing of the direct current through the coil o and come to saturation before the remaining parts 7) and c. Consequentlyl by the increasing' current in L the magnetic lines of torce are forced more and more toward e and the magnetic resistance ot and c simultaneously increases and the iield in the air gap rf, in which the fine wire movable coil is located, alters proportionately to the resistance. ln any case there will be a remanent magnetism in the parts when the coil (L is currentless, but the presence of the shunt conductors f oei's a more readily passable path for the lines of torce than through the return conductor c and the air gap, so that when coil a is currentless there will be no lines of force in c.

By using suitable material for the core parts Zw and f and by suitably dimensioning these parts it is possible to produce in the shunt members f a magnetomotive force adapted or capable of absorbingall lines of 'torce engendered in the frame b, so that when the winding or coil a is currentless, the field at (j is also at zero or. vanishes.V By suitably proportioning the elements in question it iseven possible to procure'sueh conditions-thaty the field at c increases or de- Acreases in exact proportion to the current passing through the coil a.

I Practical experiments have shown that iterl 'i the magnetic shuntmembers sucli'materials are most adapted which possess alhi'gh coercivelforce; such materials are preiterably paramagnetic metals, as for example, pure nickel. Also magnet-steel, such as employed for permanent magnets, has given a good Iresult, sufficient absorbing action being obductor are saturated.

In 'order to insure a reliable and powerful action of the shunt-conductor f,it may sometimes be necessary to magnet'lze or energize the latter strongly. This cai"l be effected by directly surrouiuling the shunt-conductor' f 'with an energizing coil, which maybe in 'series or in parallel circuit with the wire or coil a, so that the whole current to be meas- .ured or only a part. of the saine -1nay pass through the said energizing coil. ,ln Fig. l I have shown such an ei'iergizing winding or coila1 vin parallel with the winding or coil a, the coil (at on the shunt being reversely wound because the magnetic tlux through -the shunt. is in an opposite direction to that in the coi'e of coil a., while the current through e1 isin parallel and in the same direction to the working current in coil c. -In thisfigure-T L .ive merely shown the field .magnet system, it being understood that the -rotary member operates in the air-gap c.

A field system action which is ratherexactly proportional to the current, may be obtained in the following manner. The magnetic shunt-coinluctor made not so strong or powerful that, in the eurrentless state, it sucks oit or absorbs all remanent lines. of force, but is made somewhat weaker. Such a system is represented in Fig. 2, in which the magnetic shunt members f are separated by the air-gap g. The arn'iature or movable coil of the meter which is mounted lto'rotate in the air-gap'c in the usual manner, is indicated diagrannnatically by the coil Z. The conductors or leads ot' this coil! are carried up through, or may traverse, a coil in the gap y, when they are subjected to a torque due to the tlux between the magnetic shunt members f', the conduc` tors being arranged to produce a torque in opposition to thatoi the main ,coil in the air-gap 0. By using suitable material and by suitably proportioni'zig the magnetic shunt members and the length ot' the cong that when the current.' reaches its maximum, for example in shortcircuiting, lthe frame aiid the .shunt-conductors in the air-gap g, the differential action produced upon the rotary member 1 may be made exactly proportional to the cui-rent flowing through the meter.

In case the apparatus works with diii'erential action, it is not necessary to have'the opposing torque or oppositely acting iield in direct connection with the main tield. It may rather be produced by ay coil at (Fig. which is in shuntor in series with the coil (L of the main lield. The main field c is in this modification energized by the coil a and the dilferential field r/ of a separate magnetic conductor f1 by the coil a return meinber or armature is represented by the parallel branches l and Z2 which act in o 'i )osite direction. But the coil Z ot Fig. Z may he fused without any alterations in the field arrangement shown by Fig. 3, and the coil branches Z1, Z2 of Fig. 3 may .likewise be, used in the field s stem of Fig. 2.

In the diagram' Fig. 4, the ordinates of the curve fm, a p represent the tractive t'orec which proceeds from the main field and which is Vproportional to the field or te a niagnetizing curve.` By means of suitable material. and by proper dimensions ot the elements a magnetizing curve t a vr'may be obtained for the opposing torque field, the action of which is such that when the cur.- rent is zero both actions are equal to or countcrbalance each other. As is evident, the resulting tractive force is the diti'ereiu'ee ot' the ordinates of the curves rA a p ands more "exactly proportional to `the currentc sie than the original curves. 1

` The di'li'erential coil may be arranged in various ways. For a goed action it is necessary to supply tlic energizing coils as well' as the coils acting in a dynamical manner with equal or proportional currents.

lVliile I have shown in the drawings by Figs. Q and 3 only `two striking constructions, l in no wiseliinit myself thereto, as a great variety ot' combinations may be produced without involving a departure from the spirit ot my invention. The improved tielilsystein may also be4 used in needle-V instruments orlneedle electric meters.

I claimcoinprising an electro-magnet having an airgap, a stationary coil to energize the magnet,

a magnetic shunt having an energizing wind.

ing thereon and capable ot' absorbing Ithe remauent magnetism to render the field within the air-gap proportional to the current in the stationary coil.

115Y 1. A field system for direct current meters,

L. A field system tor direct current meters, j

comprising an electroanagnet having a main air-gap, a stationary coil to energize the magneti, a second coil connected in parallel with the stationary coil an'd a magnetic shunt energized by the second coil and having an air-gap and capable ot' absorbing the remanent magnetism and rendering the field in the main air-gap proportional to the current in the v.stationary coil.

3. A field System for direct current meters comprising an electro-magnet having a main air-gap, a coil to energize the same and through `which the working current passes,

-and a magnetic shunt-.having an air-gap and also energized b y the working current the path through said magneticishunt having-a lower air and higher iron reluctance than the main air-gap.

l. A tieldsystem for direct current meters comprising a magnet having an air-gap, a stationary coil to energize the.san1e by the passage therethrough ot the workingcurrent, a magnetic shunt having an air-gap, a branch coil fed by Working current to energize the shunt, said magnetic shunl hav- 'ing a low reluctance to small nnignctomotive forces, whereby it is capable otl absorbing remanent magnetism' to render the .field in the air-gap in the .magnet pro A)ortional to the current in the stationary coi 5. A. field system for direct current meters comprising a field magnet having an air-gap, a coil to energize the same by direct working current passing therethrough, a magnetic shunt for the magnet energized by working current and having a greater coercive Jforce than the magnet ca l)able of absorbincV remab la nent magnetism and thereby rendering the field Within the air-gap.proportional to the current in the stationary coil.

6. A field system for electric measuring instruments, comprising a main field magnet having an air-gap, a current winding ener gizing the same, a return magnetic conductor, and a magnetic shunt :t'or said magnet having an air-gap, and providing a path of lower reluctance lor small magnetomotive `forces than the path through the return magnetic conductor.

7. A field system for'direct current meters comprising an electro-magnet having a main air-gap, ya coil lo energize the same and through which the working current passes, and a magnetic shunt having an air-cap and having a lower reluctance for sm: l magnetomotive forces and a higher reluctance for large magnetomotive forces than the path through the main air-gap.

4S. ln a. direct current measuring instrument, an electro-magnet having an air-gap, a return magnetic conductor .for the magnet, a magnetic shunt t'or the magnet having a lower reluctance for small magnetomotive forces and a higher reluctance Vtor large magnetomotive :forces than the path through the air-gap and return magneticconductor, and a coil rotatable Within the air-gap.

f). In a direct current measuring instrument, an electro-magnet having a main airgap, a magnetic shunt having an'air-gap, an energizing` coil upon said magnet, an auxiliary energizing coil upon said magnetic shunt, said shunt having a low reluctance for low n'lagnetomotive t'orces and becoming saturated ior the normal working current,

and a coil rotatable' within the main air-gap.

Mlth WILHELM JOHN BUSCH. Witnesses:

MAX LEMCKE, ERNEST H. L. MUMMENHOFF. 

